Applications of optical fibers at high temperatures and in harsh environments demand coatings sustainable under those conditions. The goal of this work was to evaluate thermal and environmental stability of a series of commercially available and in-house formulated acrylate-based coatings. Dual and single-coat fiber designs were tested. The individual formulations included nonurethane and urethane acrylates, silicone acrylates and an organicinorganic hybrid acrylate. The “as drawn” fibers were tested for attenuation, mechanical reliability, microbend sensitivity, delamination resistance and coating stripability. Thermogravimetric analysis (TGA) was used for estimating the use temperature of the coatings. In addition, the fibers were exposed to harsh environments, including dry aging in air (150°C) and in nitrogen (250°C), autoclaving, immersion in high pressure/temperature water (up to 200°C and 2000 psi) and immersion in a hot cable gel (160°C). Based on the obtained results, the best formulations were ranked for suitability in different types of fiber application.